Who is the most truthful of this Ummah?

The Hadith the questioner is referring to is narrated concerning the noble Companion Abu Dharr Al-Ghifari, may Allah be pleased with him, about whom the Prophet, peace and blessings be upon him, said: "Neither has the dusty earth carried nor has the green sky shaded a man more truthful in speech than Abu Dharr." Al-Albani graded this Hadith authentic. The commentators explain that Abu Dharr's truthfulness is an exaggeration, and it does not mean that he is absolutely more truthful than everyone. Rather, it perhaps means that he does not use allusions or ambiguous expressions in his speech but rather reveals the pure truth. The general meaning of the Hadith indicates that Abu Dharr, may Allah be pleased with him, is the most truthful in speech of this Ummah.